The purpose of this project is to investigate in analytic studies the etiologies of selected cancers. Specific cancer sites and hypotheses are selected for which the need for investigation is clear but which have been difficult to study elsewhere. Case-control studies in progress include: childhood bladder cancer, bladder cancer in New England, cancer in rural Georgia, mycosis fungoides, nasal cancer, and testicular cancer in young men. These studies focus either on tumors that have not been studied analytically before (e.g., because of the rarity of the tumor) or on hypotheses that are difficult to assess (e.g., because of the prevalence of the exposure or the need to detect an effect at low levels of exposure). Since these studies are often the first or most thorough to date, they collect data on a wide range of exposures, usually from interviews and medical records.